770275ed0c
Right now the PVH option rom scans for the RSDP from 0xE0000 to
0xE1FFF. This is probobly a typo, it should scan from 0xE0000 to
0xFFFFF.
This is actually an issue on some QEMU versions/machines. For example,
when I run QEMU the RSDP is placed at 0xf5ad0 which will not be picked
up by the current implementation.
This bug still allows a Linux guest to boot (in most configurations) as
the kernel will just scan for the RSDP if one isn't provided.
Signed-off-by: Joe Richey <joerichey@google.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Fixes: 2785dc7b17 ("optionrom: add new PVH option rom")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
134 lines
4.4 KiB
C
134 lines
4.4 KiB
C
/*
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* PVH Option ROM for fw_cfg DMA
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright (c) 2019 Red Hat Inc.
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* Authors:
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* Stefano Garzarella <sgarzare@redhat.com>
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*/
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asm (".code32"); /* this code will be executed in protected mode */
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#include <stddef.h>
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#include <stdint.h>
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#include "optrom.h"
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#include "optrom_fw_cfg.h"
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#include "../../include/hw/xen/start_info.h"
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#define RSDP_SIGNATURE 0x2052545020445352LL /* "RSD PTR " */
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#define RSDP_AREA_ADDR 0x000E0000
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#define RSDP_AREA_SIZE 0x00020000
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#define EBDA_BASE_ADDR 0x0000040E
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#define EBDA_SIZE 1024
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#define E820_MAXENTRIES 128
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#define CMDLINE_BUFSIZE 4096
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/* e820 table filled in pvh.S using int 0x15 */
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struct pvh_e820_table {
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uint32_t entries;
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uint32_t reserved;
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struct hvm_memmap_table_entry table[E820_MAXENTRIES];
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};
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struct pvh_e820_table pvh_e820 asm("pvh_e820") __attribute__ ((aligned));
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static struct hvm_start_info start_info;
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static struct hvm_modlist_entry ramdisk_mod;
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static uint8_t cmdline_buffer[CMDLINE_BUFSIZE];
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/* Search RSDP signature. */
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static uintptr_t search_rsdp(uint32_t start_addr, uint32_t end_addr)
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{
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uint64_t *rsdp_p;
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/* RSDP signature is always on a 16 byte boundary */
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for (rsdp_p = (uint64_t *)start_addr; rsdp_p < (uint64_t *)end_addr;
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rsdp_p += 2) {
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if (*rsdp_p == RSDP_SIGNATURE) {
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return (uintptr_t)rsdp_p;
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}
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}
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return 0;
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}
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/* Force the asm name without leading underscore, even on Win32. */
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extern void pvh_load_kernel(void) asm("pvh_load_kernel");
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void pvh_load_kernel(void)
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{
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void *cmdline_addr = &cmdline_buffer;
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void *kernel_entry, *initrd_addr;
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uint32_t cmdline_size, initrd_size, fw_cfg_version = bios_cfg_version();
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start_info.magic = XEN_HVM_START_MAGIC_VALUE;
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start_info.version = 1;
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/*
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* pvh_e820 is filled in the pvh.S before to switch in protected mode,
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* because we can use int 0x15 only in real mode.
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*/
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start_info.memmap_entries = pvh_e820.entries;
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start_info.memmap_paddr = (uintptr_t)pvh_e820.table;
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/*
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* Search RSDP in the main BIOS area below 1 MB.
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* SeaBIOS store the RSDP in this area, so we try it first.
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*/
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start_info.rsdp_paddr = search_rsdp(RSDP_AREA_ADDR,
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RSDP_AREA_ADDR + RSDP_AREA_SIZE);
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/* Search RSDP in the EBDA if it is not found */
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if (!start_info.rsdp_paddr) {
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/*
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* Th EBDA address is stored at EBDA_BASE_ADDR. It contains 2 bytes
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* segment pointer to EBDA, so we must convert it to a linear address.
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*/
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uint32_t ebda_paddr = ((uint32_t)*((uint16_t *)EBDA_BASE_ADDR)) << 4;
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if (ebda_paddr > 0x400) {
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uint32_t *ebda = (uint32_t *)ebda_paddr;
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start_info.rsdp_paddr = search_rsdp(*ebda, *ebda + EBDA_SIZE);
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}
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}
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bios_cfg_read_entry(&cmdline_size, FW_CFG_CMDLINE_SIZE, 4, fw_cfg_version);
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bios_cfg_read_entry(cmdline_addr, FW_CFG_CMDLINE_DATA, cmdline_size,
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fw_cfg_version);
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start_info.cmdline_paddr = (uintptr_t)cmdline_addr;
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/* Check if we have the initrd to load */
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bios_cfg_read_entry(&initrd_size, FW_CFG_INITRD_SIZE, 4, fw_cfg_version);
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if (initrd_size) {
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bios_cfg_read_entry(&initrd_addr, FW_CFG_INITRD_ADDR, 4,
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fw_cfg_version);
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bios_cfg_read_entry(initrd_addr, FW_CFG_INITRD_DATA, initrd_size,
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fw_cfg_version);
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ramdisk_mod.paddr = (uintptr_t)initrd_addr;
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ramdisk_mod.size = initrd_size;
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/* The first module is always ramdisk. */
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start_info.modlist_paddr = (uintptr_t)&ramdisk_mod;
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start_info.nr_modules = 1;
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}
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bios_cfg_read_entry(&kernel_entry, FW_CFG_KERNEL_ENTRY, 4, fw_cfg_version);
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asm volatile("jmp *%1" : : "b"(&start_info), "c"(kernel_entry));
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}
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